Function validate_inline_enables_against_active_rules 

pub fn validate_inline_enables_against_active_rules(
    content: &str,
    flavor: MarkdownFlavor,
    active_rules: &HashSet<String>,
    ignored_for_file: &HashSet<String>,
) -> Vec<InlineConfigWarning>

Warn when an inline directive tries to ENABLE a rule that will not run over this document, so the enable has no effect.

rumdl removes disabled rules from the rule set before any file is read (filter_rules), so a disabled rule is never instantiated and inline config cannot bring it back. per-file-ignores removes further rules for the file at hand, with the same finality. active_rules is the set of canonical rule ids configuration left enabled and ignored_for_file the ids per-file-ignores then takes away; a valid rule outside the first, or inside the second, is not running.

Only recognized rule names warn. Unknown names are left to validate_inline_config_rules, a bare enable/enable-file (no rules, meaning “all”) targets no specific rule, a configure-file boolean warns only for true (an enable), never false (a disable), and a directive inside a code block enables nothing to begin with.